Equipment for forging crank-shafts



P 1, 1954 H. ROBRA 3,146,513

EQUIPMENT FOR Foacmc CRANK-Si-IAFTS Filed Sept. 28, 1960 6 Sheets-Sheet 1 r 4 i I llllmill.

I nwE/vra? H.130 bra/ H. ROBRA Sept. 1, 1964 EQUIPMENT FOR FORGING CRANK-SHAF'TS 6 Sheets-Sheet 2 Filed Sept. 28, 1960 INVIEWT'OQ Ii .Babrw Sept. 1, 1964 H. ROBRA 3,146,513

EQUIPMENT FOR FQRGING CRANK-SHAFTS I Filed Sept. 28, 1960 6 Sheets-Sheet 5 um-m INVENTOP Sept. 1, 1964 H. RoBRA 3,146,513

EQUIPMENT'FOR FORGING CRANK-SHAFTS Filed Sept. 28. 1960 6 Sheets-Sheet 4 Sept. 1, 1964 H. ROBRA EQUIPMENT FOR FORGING CRANK-SHAF'ITS 6 Sheets-Sheet 5 Filed Sept. 28, 1960 IIIIIIIIIIIIIIQIIII "nun INVENTOR flglmuffiora I BY 2M7 sag/M ATTORNEYS H. ROBRA Sept. 1, 1964 EQUIPMENT FOR FORGING CRANK-SHAFTS 6 Sheets-Sheet 6 Filed Sept. 28, 1960 FIG. 7

INVENTOR f/e/mz/f Rod/v 7 BY 9%] Ad r7 TJ M ATTORNEYS United States Patent 3,146,513 EQUIPMENT FUR FORGEWG CRANK-SHAFTS Helrnut Rohra, Walifriedsweg 24, Mulheirn (Ruhr), Germany Fiied Sept. 23, 1964 Ser. No. 139,814 (Ziairns priority, application Germany Oct. 8, 1959 4 tliairns. (Cl. 29-6) French Patent No. 1,166,978, which corresponds to USA. patent application Serial No. 641,168 (now abandoned), relates to means for the progressive forging of the throws of a crank-shaft, the punch-holder of which can travel transversely to the axis of the crank-shaft. When working with the said equipment, the crank-shaft, when the forging of the crank-throw located underneath the punch is finished, is lifted out of the forging die by means of an ejector acting from beneath, or by means of a crane, which can of course also be used for lifting the crank-shaft into the die. Under these circumstances, and particularly during the displacement, then ensuing, of the crank-shaft, and the forging of the next throw, it may easily happen that the finished throw becomes deformed, by the two crank-webs bending around the finished crank-pin in such a way that the distance between the crank-webs is diminished, and in this way the crankshaft becomes bent. In order to guard against this, a wedge has been inserted by hand during experimental work by the inventor between the crank-Webs after the lifting of the forked punch, and this should provide against the crank-webs inadmissibly approaching one another during the further treatment of the crank-shaft. On such occasions this wedge was inserted before the crank-shaft was pushed up by the ejector. This manipulation is not the known state of the art, but did not prove satisfactory, on account of the difficulty that occurred in the insertion of the wedge.

Now the object of the present invention is to facilitate the insertion of a wedge between the webs of a crank-shaft during the forging operation, and it serves this purpose in the equipment described in the above mentioned patent, the punch-holder of which can travel transversely to the axis of the crank-shaft. The invention consists in providing the punch-holder at one of its ends with a disengageable coupling means for the raising, traversing and lowering or dropping of wedges or packing pieces to be inserted between the crank-webs of the shaft.

The invention further relates to a distinctive construction of the packing pieces which is particularly suitable for the present purpose. These packing pieces also obviously admit of being brought into and lifted out of the throw of the crank-shaft by means other than the punch-holder, for instance by a crane specially provided for this purpose.

The invention is illustrated by way of example in the accompanying drawings, in which:

FIGURE 1 shows the essential parts of a forging press, with the equipment for actuating the packing pieces; while FIGURE 2 shows on a larger scale a side view of a crank-throw of a crank-shaft, with packing pieces suspended above it; and

FIGURE 3 shows a similar side view with the packing pieces inserted;

FIGURE 4 is a plan view of the parts shown in FIG- URE 3;

FIGURE 5 is a plan view, partly in section on the line VV in FIGURE 6, of a detail of FIGURE 1;

FIGURE 6 shows a cross section of the detail shown in FIGURE 5, on the line VIVI in that figure;

FIGURE 7 is a front View of one of the wedges or 3,146,513 Patented Sept. 1, 1964 ice wedge-shaped packing-pieces shown in FIGURES 2, 3 and 4;

FIGURE 8 shows a packing-piece consisting of two Wedge-shaped portions, in section on the line VIII-VIII in FIGURE 7.

A press according to FIGURE 1 has a crosshead 1, containing a hydraulic cylinder 2, in which a press plunger 3 is guided. The press plunger 3 is attached to a platen 4, which slides, with four sleeves 5, on tie-rods 6, which connect the crosshead 1 with the foundation 7. By 8 are denoted the piston rods of retracting pistons 9, which are movable up and down by hydraulic pressure in cylinders 10 in the press crosshead 1.

To the platen 4 is secured, by means of dovetail connections 11 and wedges 12, a cross-piece 13, which is also additionally held by screws 14. Into the cross-piece 13 is inserted, with a dovetail 15, a punch-holder 16, which can be displaced towards the left, out of the position represented in full lines, into the dot-and-dash position 16a. Behind the plane of section of the drawing, the punch-holder 16 carries a toothed rack 17, with which there meshes from above a toothed wheel 18, which is integral with a toothed bevel wheel that meshes with a bevel pinion 19. The bevel pinion 19 is mounted upon a shaft 21), which is driven by an electric motor 21. To the punch-holder 16 is secured, by means of a dovetail connection 22 and a wedge 23, a forked forging punch 24, which can travel into the drop-forge die or swage 25, for the purpose of forging there a crank-pin 26a of a crank-shaft 26. In the drawing the crank-pin 26a is represented as being already finish-forged, and one crank-web 26b is recognizable in an outside view. In the forging die 25, underneath the space for the crank-pin 26a, there is an ejector 27, which can be raised by introducing pressure liquid in the direction of the arrow 28a into a cylinder 28.

The arrangement so far described is not the subject of the invention.

The punch-holder 16 has an overhanging arm 29, with an eyelet 31), from which a hook 31 is suspended, and on a table 34 nearby, a number of wedges or packingpieces 32, 33 are standing ready for use. When a crankthrow has been forged, the hook 31 engages, with its lower end 31a, in a hole in a wedge or packing-piece 32, and then, upon the raising of the platen 4, the packingpiece 32 is raised with it. If the punch-holder 16 is now traversed into the position 16a, the packing-piece 32 passes into the position 32a, that is, above the throw of the crank-shaft 26. If a blow in a suitable direction is now struck against the hook 31, or if the latter is otherwise impulsively retracted, it sets the wedge 32 free, so that the latter falls down into the throw of the crankshaft. Under these circumstances the packing-piece becomes jammed, owing to its wedge-shaped form. It is also possible to postpone effecting the release of the wedge 32 from the hook 31 until after the crank-shaft 26 has been lifted to a greater or less extent by means of the ejector 27, or of a crane, not shown.

Instead of the simple wedge-shaped packing-piece 32 according to FIGURE 1, a packing-piece according to FIGURES 2 to 4 is preferably employed. This consists of two wedge-shaped portions 40 and 41. In the part 40 there is a hole 42, into which the end 31a of the hook 31 can be introduced. The wedge-shaped part 40 is so connected with the wedge-shaped part 41, by means of a dovetail connection 43, as to be longitudinally slidable. Owing to this connection the two parts 40 and 41 can move relatively to one another as far as the abutments 44 and 45 provided therein permit. In FIGURE 2 the part 41 is occupying, relatively to the part 40, its lowest pos' sible position. In FIGURE 3, on the other hand, the

two parts have slid one over the other. Two arms 46 are laterally welded on to the lower end of the part 48. Their distance apart is so great that they embrace the crank-web 26b. They each carry an arresting screw 47, with a point 48.

When the packing-piece 4t) suspended from the hook 31 in FIGURE 2 drops down, owing to an impulsive movement of the hook 31 to the right, imparted either by pulling the hook out by hand, or knocking it out with a hammer, then the two wedge-shaped parts 441 and 41 push their way, in falling, in between the two crank-webs 26b and 260, so that they assume the position shown in FIG- URE 3. In this movement the arms 46 slide along the crank-web 26b. Thereupon the screws 47 are screwed in by hand, so that an additional security is provided against the packing-piece falling out of the throw during the subsequent operations. These subsequent operations include: lifting the crank-shaft out of the die, shifting it axially through the distance that is to intervene between two adjacent crank-throws, turning it through the angle that the next crank-throw is to make with the one just forged, and lowering it until its journals rest on the bearings provided for the purpose. The packing-pieces are all removed after the forging of the crank-shaft has been completed.

I claim:

1. A method for the stepwise forging of the crankthrows of a crank-shaft, comprising the steps of: forging one crank-throw of the crank-shaft .in a forging die by means of a forging punch, raising the forging punch out of the forging die, inserting between the webs of the crank-throw a packing-piece not connectedwith the forging die, lifting the crank shaft until the crank-throw that has been forged is clear of the forging die, shifting the crank-shaft axially through a distance equal to the intended distance between two crank-pins, turning the crankshaft through an angle equal to the intended angle between adjacent crank-throws, lowering the crank-shaft into the forging die, forging another crank throw by means of the forging punch, and repeating these operations until the required number of crank-throws have beenforged, the packing-pieces remaining between the webs of the crank-throws previously forged throughout these operations.

2. Equipment for the progressive forging of the crankthrows of a crank-shaft, comprising: a forging die; a forging punch for shaping the crank-throws, crank-webs and crank-pins in the forging dieymeans for moving the punch; means for lifting a crank-shaft into and out of the forging die; and packing-pieces, not connected with the forging die, adapted to fit tightly between the crank-webs adjacent to the crank-pins of the newly forged crank-throws so as to bear against the crank-webs and maintain them at the correct distance apart, thereby guarding against bending of the crank-shaft while it is being shifted; the said packing-pieces each consisting of two parts, slidable relatively to one another to a limited extent in the direction of their length, at least one of the parts being tapered like a wedge.

3. Equipment for the progressive forging of the crankthrows of a crank-shaft as claimed in claim 6, one of the parts of the packing-piece comprising means, such as pointed screws, for securing the packing-piece to the shaft after complete insertion of the two-part packing-piece between the crank-webs.

4. Equipment for the progressive forging of the crankthrows of a crankshaft as claimed in claim 2, further comprising a punch-carrier which carries the forging punch, a track along which this punch-carrier can travel in a horizontal direction transversely to the axis of the crank-shaft and means for impelling the punch-carrier along this track, the punch-carrier comprising, at one of its ends, a disengageable coupling-piece for raising, shifting, lowering and releasing a packing-piece.

References (liter! in the file of this patent UNITED STATES PATENTS 426,071 Sanford Apr. 22, 1890 1,181,703 Warner May 2, 1916 1,252,673 Dunne Jan. 8, 1918 1,921,542 Sann Aug. 8, 1933 2,911,705 V0111 Bovert NOV. 10, 1959 3,038,385 Smith June 12, 1962 FOREIGN PATENTS 1,166,978 France June 30, 1958 15,826 Great Britain 1890 

1. A METHOD FOR THE STEPWISE FORGING OF THE CRANKTHROWS OF A CRANK-SHAFT, COMPRISING THE STEPS OF: FORGING ONE CRANK-THROW OF THE CRANK-SHAFT IN A FORGING DIE BY MEANS OF A FORGING PUNCH, RAISING THE FORGING PUNCH OUT OF THE FORGING DIE, INSERTING BETWEEN THE WEBS OF THE CRANK-THROW A PACKING-PIECE NOT CONNECTED WITH THE FORGING DIE, LIFTING THE CRANK-SHAFT UNTIL THE CRANK-THROW THAT HAS BEEN FORGED IS CLEAR OF THE FORGING DIE, SHIFTING THE CRANK-SHAFT AXIALLY THROUGH A DISTANCE EQUAL TO THE INTENDED DISTANCE BETWEEN TWO CRANK-PINS, TURNING THE CRANKSHAFT THROUGH AN ANGLE EQUAL TO THE INTENDED ANGLE BETWEEN ADJACENT CRANK-THROWS, LOWERING THE CRANK-SHAFT INTO THE FORGING DIE, FORGING ANOTHER CRANK THROW BY MEANS OF FORGING PUNCH, AND REPEATING THESE OPERATIONS UNTIL THE REQUIRED NUMBER OF CRANK-THROWS HAVE BEEN FORGED, THE PACKING-PIECES REMAINING BETWEEN THE WEBS OF THE CRANK-THROWS PREVIOUSLY FORGED THROUGHOUT THESE OPERATIONS. 